Apollo 16 - Notes on Transcription

By Tim Brandt

The Narrative

The process of producing corrected transcripts is not
straightforward, and neither can the result be described as completely
accurate and free from errors. Regrettably, there is no open source of
the original recordings of Apollo 16's mission and most of the tapes
have not been reviewed since the original transcriptions were made.
There are a few exceptions, such as periods when television
transmissions were being made. Hence, the primary source material for
this record is the transcriptions produced by the Apollo Spacecraft
Program Office (ASPO) from the tapes recorded at Mission Control
throughout each mission. In the case of Apollo 16, there are three main
transcripts:

The Technical Air to Ground Voice Transcription
This was the transcription of the technical air-to-ground voice
communications of the Apollo 16 mission. Communications recorded from
the primary communications network, and was produced immediately after
the mission in April 1972.

Command Module (CM) On-Board Voice Transcription.
This was the transcription of flight crew communications as recorded on
the CM data storage equipment (DSE) and subsequently transmitted
(dumped) to Manned Space Flight Network (MSFN) stations. Magnetic tapes
containing dumped voice and onboard recorded Apollo elapsed time (AET)
information were forwarded to ASPO, and the transcription was produced
shortly after the mission, in June 1972.

Lunar Module (LM) On-Board Voice Transcription (LM Transcription.
This was the transcription of flight crew communications as recorded on
the LM data storage equipment assembly (DSEA). After the multiplexed
voice communications and mission elapsed time had been recorded on
board the LM on a single track of the tape, the tape cassettes were
transferred to the command module (CM) for the return to Earth. The
transcription was produced shortly after the mission, in May 1972.

The Technical Transcription covers the entire mission, from shortly
before launch to splash-down 13 days later, but only records what was
transmitted to (and received by) Mission Control. For example, the
Technical Transcription includes no information when the CM and LM were
on the opposite side of the Moon to the Earth.

The CM Transcription and the LM transcription cover all the crew’s
discussions and speech in the CM and LM respectively, and some but not
all of the radio communications. However, they cover relatively short
periods of the mission, since the DSE and DSEA were not running
continually. The DSE, in particular, was only operated during periods
of significant activity such as maneuvering or during in-flight
experiments. As a result, some parts of the mission have no
transcripts. Other periods have the same speech recorded two or three
times, on the different systems. However, this brings its own
complexity, as the transcripts sometimes disagree. This is not
surprising as the recordings were reviewed and interpreted by different
people. Neither was the quality of the recordings uniformly good.
Trying to interpret unclear or garbled speech in a recording is as much
as art as a science, and two people can come to different conclusions
over the same phrase. To make life harder, "vox" circuitry was used at
times during the mission, especially when the crew were too busy to
operate switches before each radio transmission. Vox, or "voice
operated switching" starts transmitting when the user speaks into the
microphone. However, there is always a short delay before the system
can operate, with the result that the start of sentences can be
clipped, making the words and their exact timing hard to understand.
Finally, internal communication in the spacecraft is often broken or
unclear, especially when the crew were communicating without their
headsets.

The timings in the transcripts tapes pose still further problems.
Mission Control used Ground Elapsed Time (GET) as the primary means of
co-ordinating activity. GET was updated to the spacecraft, to MCC
computers, and to the telemetry down-link pulse-codemodulated bitstream
and other time-recording devices on the spacecraft. GET was updated to
correct significant changes in Flight Plan time occurring as the result
of delayed lift-off, midcourse corrections, or spacecraft burn-time
differences (trajectory dispersions). Therefore, Apollo elapsed time
(AET) (the true mission elapsed time) does not always agree with Flight
Plan and MCC times. Furthermore, radio communications takes a finite
time to travel from Mission Control, via a transmission station, to a
spacecraft in the vicinity of the Moon. This can change timings by a
second or so in either direction.

The result is a considerable challenge to the person trying to assemble
a single coherent transcription record. In this record, the Technical
Transcription has been used as the master for all Mission Control
transmissions, while the CM and LM Transcriptions have been used as the
master for radio transmissions from each
of these craft. Where there is significant disagreement between them,
this is recorded. Where the differences are not significant, the
differences have been
ignored. Where there are slight differences in timings, these have been
adjusted to ensure the sequence of conversation is correct.

The result is that while much of the transcript is clear and definitive, some parts are not.

In the transcripts, a number of notations are used to indicate
features of the recordings. Additional notations are used in the
consolidated version presented in the Flight Journal:

In the transcripts, a series of three
dots is used to designate those portions of the text that could not be
transcribed because of garbling. This is shown in the Flight Journal as
"(Garble)".

A series of three asterisks (***) is used
to designate those portions of the text that could not be transcribed
because of clipping caused by the voice actuated (VOX) mode. This is
shown in the Flight Journal as "(Vox)".

One dash (-) is used to indicate a speaker's pause or a self-interruption and subsequent completion of a thought.

Three dashes (--) are are used to
indicate an interruption by another speaker or the point at which a
recording was abruptly terminated. In the Flight Journal this is shown
by an elipsis (...).

Words given unusual emphasis by the speaker are underlined.

In the Flight Journal, "(Onboard)" is
used to designate speech that was not recorded on the technical
transcript, and that was probably only heard inside one spacecraft.

In the Flight Journal, "(Comm)" is used
to to designate speech that was not recorded on the technical
transcript, but that was probably transmitted to the other spacecraft.

Example

The following fragment gives an example of the difficulty in trying
to match CM and LM transcripts.In it, both LM and CM are in orbit
around the Moon, on their 10th revolution. The crew are preparing for
separation of the LM and CM, in preparation for Young and Duke to
descend to the Lunar surface.

CM Transcript

093 54 31 Mattingly :
We're through with the LM umbilicals, I hope.

093 54 45 Mattingly :
There's a lot of (garble) up here.

093 55 01 Mattingly :
I think it's almost as easy to (garble) it was designed (garble) Yes,
sir. I'm gonna count them (garble) at least a dozen garble) Yeah. I'll
stow them.

093 55 23 Mattingly :Yeah. We don't want to - we don't want to leave these up here. (Garble) get in the way.

093 55 49 Mattingly :Huh? What?

093 56 06 Mattingly :Yeah, we're - The only way
we'll keep from screwing up is to follow the checklist. Which comes
after - comes after the tunnel. Wait a minute. After what? No, sir. I
got a coarse align that comes 40 minutes after probe and drogue. If I
get out of sync, I'm going to make you run the (garble) Well, you're
way ahead of your time line, and I'm just barely hanging on.

093 55 46 Young: If you get into Min Dead Band Attiture hold, I can go ahead and do this coarse align.

093 55 49 Duke: Wait - Wait a - No, wait a minute. Let - you can't do it without his numbers. And he's doing the tunnel stuff now.

093 56 00 Young: Okay.

093 56 02 Duke: He wanted you to go - to do the coarse align, but let's do the tun - whatever you think's faster.

093 56 09 Mattingly:(Garble)

093 56 11 Duke: Okay. Well, that - this comes -
this comes after, Ken. The drogue and probe comes after, so why don't
you get John - after the docked align.

093 56 24 Mattingly:(Garble) coarse alignment (garble).

093 56 37 Duke: Okay, go ahead. I just didn't see that. Ours just has us at - way ahead of that.

093 56 39 Mattingly:(Garble).

093 56 42 Duke: Oh, I see what - Okay, you're
right. All I'm supposed to do is verify this stuff. Let him get that
end, John. We - we're in Fat City. Man, I'm putting a lot of load on
this suit in the back - -

Here we have two conversations going on simultaneously. Ken
Mattingly in the CM is working to prepare the CM for separation, and is
discussing this with John Young and Charlie Duke, who are doing the
same in the LM. Neither spacecraft's transcript includes the details of
the other's transmissions, although there are some clues. In addition,
the stated timings differ by approximately 3 seconds, affecting the
sequencing. An informed guess at a combined transcript is:

093 56 42 Duke (CM comm): Oh, I see what - Okay, you're right. All I'm supposed to do is verify this stuff.

093 56 42 Duke (CM onboard): Let him get that end, John. We - we're in Fat City. Man, I'm putting a lot of load on this suit in the back...

The Timings

The transcriptions all quote timing as Ground Elapsed Time (GET). This represents the elapsed time since the start of the mission. Strictly, it is the elapsed time since lift-off. In Mission Control, this was displayed as the hours, minutes and seconds. In the Command Module, GET was displayed after liftoff on the Mission Timer, also in hours, minutes and seconds. Timings in the Flight Plan were also indicated against GET, and GET provided a common timing for co-ordination of activities between Mission Control and the Crew. However, as the mission progressed, it was sometimes necessary to change the Flight Plan significantly. This happened twice on Apollo 16.

The first time was at 118:30 GET, when the mission clock was put forward by 11 minutes and 40 seconds. This was due to the delay to the Powered Descent Initiation after a fault was found in the Service Propulsion System. This delay rippled through most of the activities as the CSM's orbit about the Moon was not as planned. As a result, key timings such as acquisition of signal times, loss of signal times and the events in between were not as listed in the flight plan. The change of 11 minutes and 48 seconds realigned these, although it did not prevent a large number of other Flight Plan changes.

The second time was at 202:18 GET, when the mission clock was put forward a further 24 hours, 34 minutes and 12 seconds to account for the decision to cut the mission short and leave lunar orbit one day early. This resulted in a total time difference of 24 hours, 45 minutes and 52 seconds.

In each case, the Mission Timer was updated remotely by Mission Control. These changes realigned the time displayed to most of the subsequent timings in the Flight Plan.

To keep a single narrative of the mission, all events in this combined transcript follow the example and quote GET since liftoff - the "actual GET". However, since Mission Control, Crew and the Public Affairs Officer all quote GET as including the mission clock resets, when any timing is being quoted by any of these parties it will be shown as communicated (ie the amended GET) but the actual GET will be shown in [square brackets].